Pack Year Calculator
Calculate your smoking history in pack-years (packs per day × years smoked) for clinical lung cancer risk assessment.
Use the Pack Year Calculator
Smoking History
Enter your average daily cigarette count and years smoked.
One pack = 20 cigarettes.
Result
Enter your smoking history and click Calculate.
This calculator is for educational purposes only. Consult a licensed healthcare provider for medical advice and screening decisions.
Summary
A pack-year is a standardized clinical unit that quantifies cumulative tobacco exposure. It is calculated by multiplying the average number of cigarette packs smoked per day by the total number of years smoked. Clinicians use this figure to assess lung cancer screening eligibility (e.g., USPSTF criteria) and to stratify COPD, cardiovascular, and surgical risk.
How it works
- Enter the average number of cigarettes you smoke (or smoked) per day.
- Enter the total number of years you have smoked.
- The calculator divides cigarettes per day by 20 to get packs per day.
- Packs per day is multiplied by years smoked to produce the pack-year total.
- A risk summary based on common clinical thresholds is displayed.
- Use the result in conversations with your healthcare provider.
Use cases
- Determine eligibility for annual low-dose CT lung cancer screening.
- Document smoking history for surgical pre-assessment.
- Stratify COPD and cardiovascular risk in primary care.
- Support pulmonology referrals requiring a quantified smoking history.
- Patient education — visualize cumulative tobacco exposure.
- Research and clinical trial enrollment screening.